Many home and small businesses use of printers, copiers, facsimile machine, multifunction device, and the like, utilize expensive toner cartridges. These toner cartridges generally correspond to non-magnetic development systems, which may or may use conventionally or chemically manufactured toner. Conventional toner is generally formed using a pulverization technique that forms the small toner particles from larger manufactured toner components. Uniformity in size and shape of the resulting small toner particles does not generally result. In contrast, chemically manufactured toners are generally uniform in size and shape. Two recognized types of chemically produced toners include suspension polymerization toner and an emulsion aggregation toner. As these toners have smaller particles than conventional toners, less toner need be manufactured and used to provide comparable, if not higher quality, print results.
In some conventional toner cartridges, toner is filled into a cartridge sump, and a paddle, or gravity, is used to load a supply roller with toner, which is then transferred to a development roll. As the development roll rotates, the toner is charged and metered in the nip of the charge/metering blade that is held in contact against the roll with a pre-determined force. After the blade, enough charged toner is brought into a development zone to support good solid area and halftone uniformity on the latent image on a photoreceptor. The blade is typically a thin piece of steel, bronze or copper that is mounted onto a rigid holder that is mounted to the development housing. The physical properties and the dimensions of the blade (i.e. modulus, thickness, free length, etc.) are selected to provide an optimal normal force against the development that will provide good charging and metering of the toner that enters into the nip formed between the two. This contact width is typically less than one millimeter in the process direction. Toner must be able to charge and flow well enough in this one-millimeter nip to enable a sufficiently charged developed mass on the photoreceptor when brought into contact with the latent image. Such operations and configurations work well with conventional toners and certain chemically produced toners.
However, such a cartridge is ineffective to sufficiently charge toner chemically produced by means of the emulsion aggregation process, as set forth in U.S. Pat. No. 5,747,215, the entirety of which is incorporated by reference herein. For example, toners produced using the suspension polymerization process can achieve a tribo charge of 30-40 uC/gm with 0.3-0.4 mg/cm2 of toner mass on the roll prior to development. In contrast, emulsion aggregation toners typically reach 15-20 uC/gm at approximately the same amount of toner mass on the roll prior to development. Thus, there is a need for a simple and easily implemented apparatus, module, and system to increase the tribo charge of emulsion aggregation toners in existing toner cartridges without incurring any substantial increase in the cost of materials, redesign, or manufacture.